Patent Document 1 describes a method which carries out so-called terminal pairing to link terminals having a near field communication function, such as Bluetooth in association with each other. The method described in Patent Document 1 allows simple selection of a terminal to be paired even when there are other multiple terminals near the terminal to be paired.
According to the method described in Patent Document 1, first, a terminal which finds a terminal gradually increases the output of an electric wave for terminal finding and expands the access range of the electric wave in a stepwise manner. Each time a terminal is found, the terminal which finds a terminal stores the found terminal and the steps of the access range of the electric wave at that time together. Next, the terminal which finds a terminal presents each found terminal to a user in each step of the access range of the electric wave at the time of finding, and causes the user to select a terminal to be paired.
Patent Document 2 describes a pairing method in which terminals transmit identification information each other to carry out authentication.